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Objective: To analyze the epidemiological characteristics of pulmonary tuberculosis (PTB) in Fengtai District from 2011 to 2021. Methods: A retrospective study was conducted, the data of PTB patients in Fengtai District from 2011 to 2021 were collected in Chinese disease prevention and Control Information System, which included etiological classification, gender, age, occupation, onset time, demographic information etc. the epidemiological characteristics of reported PTB patients was analysis. Results: A total of 10 342 cases of PTB were reported from 2011 to 2021 in Fengtai District, with an average annual reported incidence rate of 42.87/ 100 000. The incidence rate was the highest in 2012(75.89/100 000), and significantly declined from 2013, which declined to 29.70/100 000 in 2017. It showed a slow rise from 2018 to 2021. The difference was statistically significant (χ2=1 471.77,P<0.001).There were 2 975 cases of etiologic positive PTB from 2011 to 2021, and 76 cases of Rifampicin-resistant PTB from 2017 to 2021. The ratio of male cases to female was 1.75, the average annual incidence rate of male (53.94/100 000) was higher, than female(31.57/100 000).(χ2=704.01,P<0.001). Among all age groups, 25-29 years group, 20-24 years group and 30-34 years group had the highest proportion, which were 1 506 cases (14.56%) , 1 292 cases (12.49%) and 1 024 cases (9.90%) respectively. The average annual incidence rate was the lowest in the group less than 10 years old (1.43/100 000), and the highest in the group 85 years old and over (195.20/100 000), the difference was statistically significant(χ2=3164.24, P<0.001). The top occupations from high to low were housework and unemployment (2 917 cases, 28.21%), retirees (2 308 cases, 22.32%), workers (1 047 cases, 10.12%), cadres and staff (950 cases, 9.19%), farmers (860 cases, 8.32%), business services (698 cases, 6.75%), teachers and students (455 cases, 4.40%). Conclusion: From 2011 to 2021, the incidence rate of PTB was decreased from 2012 to 2017, and slowly increased lately in Fengtai District. The epidemiological characteristics of PTB vary in different age and gender.
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Rifampina , Tuberculose Pulmonar , Adulto , Idoso de 80 Anos ou mais , Pequim , Criança , China/epidemiologia , Feminino , Humanos , Incidência , Masculino , Estudos Retrospectivos , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/prevenção & controleRESUMO
BACKGROUND: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder of the central nervous system (CNS). Interleukin (IL)-6 and IL-17A may play important roles in the pathogenesis of this disease. High-mobility group box protein 1 (HMGB1), a small but highly conserved ubiquitous protein, is recognized to be a potent innate inflammatory mediator that can activate the nuclear factor light chain enhancer of activated B cells and release cytokines such as IL-6 and IL-17A when released extracellularly. However, whether cerebrospinal fluid (CSF) HMGB1 levels are altered in anti-NMDAR encephalitis is still unclear. OBJECTIVE: The aim of this study was to determine whether a correlation exists between the CSF concentrations of HMGB1 and IL-6 and IL-17A in anti-NMDAR encephalitis patients. We also sought to assess whether HMGB1 influences the clinical outcomes in anti-NMDAR encephalitis patients. METHODS: Thirty-three patients with anti-NMDAR antibodies and 38 controls were recruited. CSF HMGB1 was measured using an enzyme-linked immunosorbent assay. The main clinical outcomes were evaluated using the modified Rankin scale (mRS). The data were extracted using microarray analysis software. RESULTS AND CONCLUSION: Our results showed significant increases in CSF HMGB1, IL-6, and IL-17A (P < .05) in anti-NMDAR encephalitis patients. But between 3 months' mRS scores in anti-NMDAR encephalitis patients and CSF data, there was no correlation. Our study suggests that HMGB1 CSF levels are increased in patients with anti-NMDAR encephalitis and reflect the underlying neuroinflammatory process.
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Encefalite Antirreceptor de N-Metil-D-Aspartato/líquido cefalorraquidiano , Proteína HMGB1/líquido cefalorraquidiano , Interleucina-6/líquido cefalorraquidiano , Adulto , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Interleucina-17/líquido cefalorraquidiano , MasculinoRESUMO
A simple, sensitive, reliable method was developed for the simultaneous determination of organochlorine and pyrethriod pesticide residues in Chinese patent medicines Six ingredient rehmannia pills and Xiaoyao pills. These pesticides were extracted by ethyl acetate. The extraction time and volume of ethyl acetate were optimized. Cleanup of extracts was performed with dispersive-solid phase extraction using graphitized carbon black as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-tandem mass spectrometry in multiple reaction monitoring mode (GC-MS/MS, MRM). The linearity of the calibration curves is good in matrix-matched standard and yields the coefficients of determination (R2) ≥0.99 for all of the target analytes. Under optimized conditions, the average recoveries (five replicates) for most pesticides range from 75.5% to 114.6%, and RSDs are less than 10.0%. The LODs of 18 pesticides in Six ingredient rehmannia pill and Xiaoyao pills are in the range of 0.01-8.82 µg kg-1. The developed method meets the requirements of pesticide residue analysis and could be effectively used for routine analysis of the organochlorine and pyrethriod pesticide residues in Six ingredient rehmannia pills and Xiaoyao pills.
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Medicamentos de Ervas Chinesas/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resíduos de Praguicidas/análise , Piretrinas/análise , Espectrometria de Massas em Tandem/métodos , Calibragem , Medicamentos de Ervas Chinesas/química , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/química , Limite de Detecção , Medicamentos sem Prescrição , Piretrinas/química , Extração em Fase Sólida/métodosRESUMO
OBJECTIVE: We performed a systematic review and meta-analysis to explore the clinical application of Chinese herbal medicine (CHM) for chemotherapy-induced leucopenia and to evaluate its effectiveness and safety. METHODS: We included randomized clinical trials (RCTs) with no limitation of publication type or language. Participants were cancer patients undergoing chemotherapy. Trial designs included comparisons of CHM with granulocyte colony-stimulating factor, supportive treatments for leucopenia, and/or placebo. Main outcomes were white blood cell count and incidence of leucopenia. Screening, data extraction, and analysis were conducted according to the PRISMA guidelines. RESULTS: Eighty-three RCTs (n = 8,012) met the inclusion criteria. Fifteen Chinese patent medicines and 47 different modified formulas were used as prophylaxis for chemotherapy-induced leucopenia. Compared with no treatment, CHMs were shown to decrease the incidence of leucopenia (odds ratio (OR) -0.23 [-0.20, -0.27]), P < 0.00001), with the number needed to treat (NNT) -3.45 [-3.13, -3.85]. Subgroup analysis suggested a prophylactic benefit for white blood cell counts with Fufang E-jiao Jiang, Diyu Shengbai Pian, combination Huangqi and Shengmai Zhusheye, and Fuzhong Shengbai Fang for patients undergoing chemotherapy. No serious adverse events were reported. Only three articles (3/83, 4 %) were rated as having adequate methodological quality with a low level of bias. Funnel plots were asymmetrical. CONCLUSIONS: Some CHMs may be efficacious in the treatment of chemotherapy-induced leucopenia, but the majority of reviewed studies were of poor quality. Results need to be confirmed in rigorously conducted high-quality trials, including pharmacokinetic studies to ensure that there are no interactions between the CHM agent and chemotherapy.
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Neutropenia Febril Induzida por Quimioterapia/prevenção & controle , Medicamentos de Ervas Chinesas/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Neoplasias/tratamento farmacológico , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Povo Asiático , Medicamentos de Ervas Chinesas/efeitos adversos , Necessidades e Demandas de Serviços de Saúde , Humanos , Contagem de Leucócitos , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
OBJECTIVE: Mice injected with Bacillus Calmette-Guérin (BCG) were challenged with lipopolysaccharide (LPS) to induce inflammatory liver injury. This study was performed to explore the protective effects of interleukin (IL)-4 against liver injury induced by BCG and LPS in mice. MATERIALS AND METHODS: Mice injected with BCG (125 mg/kg) were challenged with LPS (10 µg/kg) to induce the model of inflammatory liver injury. Half an hour after injection of LPS, mice were subcutaneously administered rmIL-4 at 5 and 0.5 µg/kg, respectively. Liver injury was evaluated by serum transaminase assay and H & E staining. Liver cytokine concentrations were determined by enzyme-linked immunosorbent assay, and intrahepatic cytokine and iNOS mRNA levels by reverse transcriptase polymerase chain reaction. Intrahepatic apoptosis was evaluated by terminal deoxynucleotidyl transferase mediated nick end labeling. NF-κB p65 and ERK signal pathway was detected by Western-blotting. NF-κB signal pathway was also detected by electrophoretic mobility shift assay. RESULTS: IL-4 reduced the serum ALT, AST and LDH, alleviated the inflammatory cells infiltration, down regulated the expression of TNF-α, IL-1ß, IFN-γ, IL-6 and iNOS mRNA in liver, and alleviated hepatic glutathione depletion (GSH). In addition, IL-4 displayed inhibition of extracellular signal-regulated kinase phosphorylation and NF-κB activation. CONCLUSION: IL-4 may protect mice against BCG/LPS-induced immune liver injury, besides ERK and NF-κB signal pathways were involved in the effects.
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Interleucina-4/metabolismo , Lipopolissacarídeos/metabolismo , Mycobacterium bovis/metabolismo , Alanina Transaminase/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Feminino , Inflamação/tratamento farmacológico , Interferon gama/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , L-Lactato Desidrogenase/metabolismo , Fígado/lesões , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico Sintase Tipo II/metabolismo , RNA Mensageiro/metabolismo , Temperatura , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Gas chromatography with nitrogen phosphorus detector (GC-NPD) was applied to the simultaneous determination of 15 organophosphorus and 6 organonitrogen pesticides residues in Angelica sinensis. The pesticides were extracted by microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) techniques, respectively. The experimental variables were optimized through orthogonal array experimental design. Cleanup of extracts was performed with column chromatography using florisil and neutral aluminum as the sorbents. The determination of pesticides in the final extracts was carried out by GC-NPD. Under optimized conditions, the average recoveries obtained from MAE and UAE are in the range of 75.1-129% and 70.6-129%, respectively, and the relative standard deviations of MAE and UAE were 3.1-10.6% and 1.0-17.8%, respectively.
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Angelica sinensis/química , Compostos de Nitrogênio/análise , Compostos Organofosforados/análise , Resíduos de Praguicidas/análise , Cromatografia Gasosa-Espectrometria de Massas , Micro-Ondas , Padrões de Referência , Reprodutibilidade dos Testes , UltrassomRESUMO
Previous studies from our lab have demonstrated that upon exposure to physiologic levels of cyclic stretch, alveolar epithelial cells demonstrate a significant decrease in the amount of polymerized tubulin (Geiger et al., Gene Therapy 2006;13:725-731). However, not all microtubules are disassembled, although the mechanisms or implications of this were unknown. Using immunofluorescence microscopy, Western blotting, and immunohistochemistry approaches, we have compared the levels of acetylated tubulin in stretched and unstretched A549 cells and in murine lungs. In cultured cells exposed to cyclic stretch (10% change in basement membrane surface area at 0.25 Hz), nearly all of the remaining microtubules were acetylated, as demonstrated using immunofluorescence microscopy. In murine lungs ventilated for 20 minutes at 12 to 20 ml/kg followed by 48 hours of spontaneous breathing or for 3 hours at 16 to 40 ml/kg, levels of acetylated tubulin were increased in the peripheral lung. In both our in vitro and in vivo studies, we have found that mild to moderate levels of cyclic stretch significantly increases tubulin acetylation in a magnitude- and duration-dependent manner. This appears to be due to a decrease in histone deacetylase 6 activity (HDAC6), the major tubulin deacetylase. Since it has been previously shown that acetylated microtubules are positively correlated to a more stable population of microtubules, this result suggests that microtubule stability may be increased by cyclic stretch, and that tubulin acetylation is one way in which cells respond to changes in exogenous mechanical forces.
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Histona Desacetilases/metabolismo , Pulmão , Microtúbulos/metabolismo , Tubulina (Proteína)/metabolismo , Acetilação , Animais , Células Cultivadas , Elasticidade , Células Epiteliais/citologia , Células Epiteliais/fisiologia , Feminino , Desacetilase 6 de Histona , Histona Desacetilases/genética , Humanos , Pulmão/citologia , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Periodicidade , Respiração com Pressão Positiva , Alvéolos Pulmonares/citologia , Mucosa Respiratória/citologia , Estresse Mecânico , Transcrição Gênica , Tubulina (Proteína)/genéticaRESUMO
OBJECTIVE: The associations between dietary fat intake and cognitive function are inconsistent and inconclusive. This study aimed to provide a quantitative synthesis of prospective cohort studies on the relationship between dietary fat intake and cognitive function among older adults. METHODS: PubMed, EMBASE, PsycINFO and Web of Science databases were searched for prospective cohort studies published in English before March 2018 reporting cognitive outcomes in relation to dietary fat intake. Four binary incident outcomes included were mild cognitive impairment (MCI), dementia, Alzheimer disease (AD) and cognitive impairment. The categories of dietary fat intake were based on fat consumption or the percentage of energy from fat consumption, including dichotomies, tertiles, quartiles and quintiles. The relative risk (RR) with the corresponding 95% confidence intervals (CIs) was pooled using a random effects model. RESULTS: Nine studies covering a total of 23,402 participants were included. Compared with the lowest category of consumption, the highest category of saturated fat intake was associated with an increased risk of cognitive impairment (RR = 1.40; 95% CI: 1.02-1.91) and AD (RR: 1.87, 95% CI: 1.09-3.20). The total and unsaturated fat intake was not statistically associated with cognitive outcomes with significant between-study heterogeneity. CONCLUSION: This study reported a detrimental association between saturated fat intake and cognitive impairment and mixed results between unsaturated fat intake and selected cognitive outcomes. Given the substantial heterogeneity in the sample size and methodology used across studies, the evidence presented here should be interpreted with caution.
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Cognição/fisiologia , Disfunção Cognitiva/epidemiologia , Gorduras na Dieta/efeitos adversos , Fatores Etários , Estudos de Coortes , Humanos , Estudos Prospectivos , Fatores de RiscoRESUMO
Objective: To carry out a quantitative estimate that related to the effects of short-term exposure to PM(2.5) on all-cause mortality and emergency visits in China by using the systematic review and Meta-analysis. Methods: We selected all the studies published before March 2018 from China National Knowledge Infrastructure, Wanfang database, PubMed and EMBASE and data on relative risk (RR), excess risk (ER) and their 95%CIs: appeared in these papers were extracted. According to the differences in the size or direction (heterogeneity) of the results, we computed summary estimates of the effect values using a random-effect or fixed effect model. We also conducted the subgroup analysis and Meta-analysis to have assessed the selected studies for the evidence of study bias. Results: A total of 33 original studies, indexed in databases, were identified. Among those studies, 39 sets of data on mortality and 4 sets of data on emergency were valid to show that within the daily concentration range from 47.7 to 176.7 µg/m(3), for 10 µg/m(3) increases in PM(2.5) concentrations, it would increase the daily numbers of deaths by 0.49% (95%CI: 0.39%-0.59%) and 0.30% (95%CI: 0.10%-0.51%) for all-cause deaths and all-cause emergency-room visits, respectively. For subgroup analysis, the combined effect of PM(2.5) in causing short-term all-cause deaths in the northern areas (ER=0.42%, 95%CI: 0.30%-0.54%) seemed lower than that in the southern areas (ER=0.63%, 95%CI: 0.44%-0.82%). The combined effect of PM(2.5) concentration below 75 µg/m(3) (ER=0.50%, 95%CI: 0.37%-0.62%) was higher than that of PM(2.5) concentration ≥75 µg/m(3) (ER=0.39%, 95%CI: 0.26%-0.52%). Conclusion: Within the concentration range from 47.7 to 176.7 µg/m(3), short-term exposure to current level of PM(2.5) might increase both the all-cause daily mortality and daily emergency visits in China.
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Poluição do Ar/estatística & dados numéricos , Serviço Hospitalar de Emergência/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Material Particulado/toxicidade , Poluentes Atmosféricos , Poluição do Ar/efeitos adversos , China , Bases de Dados Factuais , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Masculino , Fatores de TempoRESUMO
PURPOSE: To test if active breath control during cone-beam computed tomography (CBCT) could improve planning target volume during accelerated partial breast radiotherapy for breast cancer. METHODS: Patients who were more than 40 years old, underwent breast-conserving dissection and planned for accelerated partial breast irradiation, and with postoperative staging limited to T1-2 N0 M0, or postoperative staging T2 lesion no larger than 3cm with a negative surgical margin greater than 2mm were enrolled. Patients with lobular carcinoma or extensive ductal carcinoma in situ were excluded. CBCT images were obtained pre-correction, post-correction and post-treatment. Set-up errors were recorded at left-right, anterior-posterior and superior-inferior directions. The differences between these CBCT images, as well as calculated radiation doses, were compared between patients with active breath control or free breathing. RESULTS: Forty patients were enrolled, among them 25 had active breath control. A total of 836 CBCT images were obtained for analysis. CBCT significantly reduced planning target volume. However, active breath control did not show significant benefit in decreasing planning target volume margin and the doses of organ-at-risk when compared to free breathing. CONCLUSION: CBCT, but not active breath control, could reduce planning target volume during accelerated partial breast irradiation.
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Neoplasias da Mama/radioterapia , Tomografia Computadorizada de Feixe Cônico/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Respiração , Adulto , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Bacillus thuringiensis is the most widely used biological pesticide in the world. It belongs to the Bacillus cereus sensu lato group, which contains six species. Among these six species, B. thuringiensis, B. anthracis, and B. cereus have a low genetic diversity. B. thuringiensis strain HD521 shows maroon colony which is different from most of the B. thuringiensis strains. Strain HD521 also displays an ability to inhibit plant sheath blight disease pathogen (Rhizoctonia solani AG1 IB) growth and can form bipyramidal parasporal crystals consisting of three cry7 genes. These crystals have an insecticidal activity against Henosepilachna vigintioctomaculata larva (Coleoptera). Here we report the complete genome sequence of strain HD521, which has one chromosome and six circular plasmids.
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In order to find a versatile high speed counter-current chromatography solvent system that can be used as a general prefractionation system for most alkaloids, the crude extracts of five Chinese traditional medicinal herbs, Cortex phellodendri, Semen strychni, green tea, Sophora flavescens ait, and Datura mete L. were resolved. All separations were performed only with a two-phase system composed of CHCl3-CH3OH-water (4:3:2). The water had different acidities controlled by adding NaH2PO4 or HCl to each sample. The fractionated components were identified by thin-layer chromatography, which confirmed this solvent system was versatile and very useful for the separation of alkaloids.
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Alcaloides/isolamento & purificação , Distribuição Contracorrente/métodos , Medicamentos de Ervas Chinesas/química , Cromatografia em Camada Fina , SolventesRESUMO
For use in micro-patterned scaffolds in tissue engineering, novel diacrylated triblock macromers (PLA-b-PCL-b-PLA, PGA-b-PCL-b-PGA and PCL-b-PEO-b-PCL) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). All diacrylated polymers were designed as triblock copolymers and involved biodegradable blocks of relatively non-polar epsilon-caprolactone (CL) and polar monomers such as glycolide (GA), lactide (LA) or ethylene oxide (EO). All triblock polymers were prepared in molecular weights of a few kilo daltons via the anionic ring-opening polymerization (ROP) of the corresponding lactide, glycolide or caprolactone using stannous octoate [Sn(Oct)(2)] as catalyst. The polymers had low polydispersity indices, ranging from 1.23 to 1.56. Biodegradable polymeric networks were prepared with conversions of 72-84% via photopolymerization of the triblock diacrylated polymers with 2,2-dimethoxy-2-phenylacetophenone (DMPA) as photoinitiator. PLA-b-PCL-b-PLA copolymers crumbled easily and were not suitable for micro-patterning. PGA-b-PCL-b-PGA copolymers had higher water contact angles than PCL-b-PEO-b-PCL and were also cytocompatible with Fibroblasts 3T3.
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Polímeros/síntese química , Engenharia Tecidual , Células 3T3 , Animais , Biodegradação Ambiental , Meios de Cultura , Espectroscopia de Ressonância Magnética , Camundongos , Peso Molecular , Polímeros/química , Propriedades de SuperfícieRESUMO
Since the discovery of the inflammasome, interleukin 1 production has been found to be integral in the pathophysiology of gout. Interleukin 1 inhibition by Anakinra has been shown to effective for the treatment of gout. We report three cases of resistant chronic tophaceous gout who responded to anakinra subcutaneous injections on an intermittent basis.
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Supressores da Gota/uso terapêutico , Gota/tratamento farmacológico , Proteína Antagonista do Receptor de Interleucina 1/uso terapêutico , Interleucina-1/antagonistas & inibidores , Doença Aguda , Idoso , Alopurinol/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Doença Crônica , Colchicina/uso terapêutico , Resistência a Medicamentos/efeitos dos fármacos , Gota/metabolismo , Gota/fisiopatologia , Humanos , Injeções Subcutâneas , Interleucina-1/metabolismo , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
Sorghum ergot, caused predominantly by Claviceps africana Frederickson, Mantle, de Milliano, is a significant threat to the sorghum industry worldwide. The objectives of this study were firstly, to identify molecular markers linked to ergot resistance and to two pollen traits, pollen quantity (PQ) and pollen viability (PV), and secondly, to assess the relationship between the two pollen traits and ergot resistance in sorghum. A genetic linkage map of sorghum RIL population R931945-2-2 x IS 8525 (resistance source) was constructed using 303 markers including 36 SSR, 117 AFLP , 148 DArT and two morphological trait loci. Composite interval mapping identified nine, five, and four QTL linked to molecular markers for percentage ergot infection (PCERGOT), PQ and PV, respectively, at a LOD >2.0. Co-location/linkage of QTL were identified on four chromosomes while other QTL for the three traits mapped independently, indicating that both pollen and non pollen-based mechanisms of ergot resistance were operating in this sorghum population. Of the nine QTL identified for PCERGOT, five were identified using the overall data set while four were specific to the group data sets defined by temperature and humidity. QTL identified on SBI-02 and SBI-06 were further validated in additional populations. This is the first report of QTL associated with ergot resistance in sorghum. The markers reported herein could be used for marker-assisted selection for this important disease of sorghum.
Assuntos
Claviceps/fisiologia , Imunidade Inata/genética , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Locos de Características Quantitativas/genética , Sorghum/genética , Sorghum/microbiologia , Sobrevivência Celular , Cromossomos de Plantas/genética , Cruzamentos Genéticos , Meio Ambiente , Epistasia Genética , Ligação Genética , Endogamia , Fenótipo , Doenças das Plantas/microbiologia , Pólen/citologia , Pólen/genética , Característica Quantitativa Herdável , Reprodutibilidade dos Testes , Sorghum/imunologiaRESUMO
We have demonstrated that COS7 cells transiently co-expressing myristylation-defective (Myr-) and protease-defective (PR-) human immunodeficiency virus (HIV) mutants can release infectious virions when co-transfected with an amphotropic murine leukaemia virus envelope protein expression plasmid (SV-A-MLV-env). In contrast, no infectious virions were detected when a PR-, noninfectious HIV gag mutant was co-expressed with the Myr- mutant, although the Myr- mutant could still process the immature core particles in trans. This result indicates that generation of functionally normal Gag proteins is required for virus infectivity in our complementation system. A mutant with a 56-amino-acid deletion in the N-terminal region of the capsid (CA) domain could still complement the PR- mutant to generate infectious virions, suggesting that the deletion mutant could provide a functional protease for processing in the PR- mutant. This result is consistent with the concept that mutations within the N-terminal region of the CA domain have no major effects on Gag-Pol incorporation into particles.